Re: By The Dawn's Normal Light

From: Kenneth Downs <firstinit.lastname_at_lastnameplusfam.net>
Date: Wed, 27 Oct 2004 18:47:28 -0400
Message-ID: <4i8plc.bug.ln_at_mercury.downsfam.net>


Laconic2 wrote:

>
> "erk" <eric.kaun_at_pnc.com> wrote in message
> news:1098899907.484940.109850_at_f14g2000cwb.googlegroups.com...

>> I can buy that atomicity is relative... that seems reasonable. So from
>> the point of view of relational theory, sets and lists have no
>> structure (their operators can do whatever they like, as with any other
>> type), but relations do.
>>

>
> The trouble comes when a relation can have an attribute whose domain is a
> relation. Now there's an incestuous relationship between the relational
> engine and the type engine. The type engine has to know about relations,
> in order to be a type engine. The relational engine has to know about
> relations in order to be a relational engine. But do they each know that
> the other one also knows?

This is a penetrating insight. The various discussions on 1NF, atomicity and so forth have made good reading, and me thinking, "hmmm, maybe there is something to this..." but it still seems that anything you want to represent can be done with the simple man's definitions of 1NF, 2NF and 3NF. But trying to turn lists into tables and vice-versa is definitely a no-starter with SQL, you have to go to an outside language.

-- 
Kenneth Downs
Use first initial plus last name at last name plus literal "fam.net" to
email me
Received on Thu Oct 28 2004 - 00:47:28 CEST

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